In recent years, normal and pathological brain iron have attracted renewed interest because of concern that some common disorders such as Parkinson's disease and Alzheimer's dementia are associated with changes in local iron metabolism. Magnetic resonance imaging now permits the visualization of normal brain iron in the substantia nigra, the red nuclei, the dentate nuclei, and the globus pallidus, and the stepwise conversion of extravasated hemoglobin iron to hemosiderin. The cellular events accompanying this conversion have been clarified by the immunocytochemical and ultrastructural visualization of ferritin in microglia, and of the ferritin repressor protein in astrocytes. In addition to ferritin, other iron-carrying proteins have been found in brain. Among these proteins, transferrin has become prominent as an immunocytochemical marker of oligodendroglia and as an indicator of oligodendroglial maturation during myelination. The severity of stroke and trauma may depend in part on iron-catalyzed lipid peroxidation, and the accelerated biosynthesis of heavy ferritin is thought to be an important defense mechanism against tissue injury. Despite the recent advances in the knowledge of distribution and cellular localization, brain iron continues to be quite enigmatic. The proposed satellite symposium seeks to bring together selected experts in the field of normal and pathological brain iron and will include students of iron imaging and iron-catalyzed lipid peroxidation. The conference will also resolve questions about the role of transferrin and the transferrin receptor in the transport of mobile iron across the blood brain barrier, the importance of microglia in the resolution of hemorrhagic brain lesions, and the behavior of brain iron during growth and systemic iron deficiency.